allow specifying odbc connection string via env

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "odbc2parquet"
-version = "0.12.0"
+version = "0.12.1"
 authors = ["Markus Klein"]
 edition = "2021"
 repository = "https://github.com/pacman82/odbc2parquet"

Changelog.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## 0.12.1
+
+* Allow specifying ODBC connection string via environment variable `ODBC_CONNECTION_STRING` instead of `--connection_string` option.
+
 ## 0.12.0
 
 * Pad suffixes `_01` with leading zeroes to make the file names more friendly for lexical sorting if splitting fetch output. Number is padded to two digits by default.

src/main.rs

@@ -81,7 +81,7 @@ struct ConnectOpts {
     prompt: bool,
     /// The connection string used to connect to the ODBC data source. Alternatively you may specify
     /// the ODBC dsn.
-    #[clap(long, short = 'c')]
+    #[clap(long, short = 'c', env = "ODBC_CONNECTION_STRING")]
     connection_string: Option<String>,
     /// ODBC Data Source Name. Either this or the connection string must be specified to identify
     /// the datasource. Data source name (dsn) and connection string, may not be specified both.

tests/lib.rs

@@ -479,6 +479,7 @@ fn query_timestamp_with_timezone_mssql() {
     // Setup table for test
     let table_name = "QueryTimestampWithTimezoneMssql";
     let conn = ENV.connect_with_connection_string(MSSQL).unwrap();
+    // ODBC data type: SqlDataType(-155), column_size: 34, decimal_digits: 7
     setup_empty_table(&conn, table_name, &["DATETIMEOFFSET"]).unwrap();
     let insert = format!(
         "INSERT INTO {}